Turbo Leak 671 TI

[John Dickson]

I need some assistance in determining where this turbo is leaking. Is it a seal or a gasket beneath the clamp? Does this look familar to any of you? What would be my next course of action for repair? Thanks for the help!
John

[Genesis]

That is a NASTY exhaust leak and has been going on a while (or is fairly extreme)

Its difficult to know exactly where it is coming from, but you need to find it pronto. With the carbon all over the intake side and relative lack of it on the pipe outbound my guess is that it is in the seal between the exhaust housing and the center section, but its hard to know for sure. The way I find these is to start with a dead cold engine, have someone start it and spray a soapy solution on all the joints - you'll see bubbles where the leak is. This has to be done on a COLD engine and immediately on start as that part of the exhaust gets hot FAST and will evaporate off the solution before it can bubble (putting cold water on hot cast iron is a great way to have it crack too.) If its the center section to exhaust housing that is leaking it is a near certainty that erosion has occurred on the mating pieces and the turbo needs reconditioning or replacement. You can use Sikaflex on the exhaust flange to pipe joint (I do UNLESS there is a high-temp gasket in there) but I wouldn't attempt it on the hotside center-section to housing joint as any that gets mobile in there could cause the turbo to grenade under load.

The potentially-very-bad news you may have a MAJOR problem in your airbox. Pull those inspection covers and have a look. Some gunk is not serious but if it is up to the level of the ports on the liners (or worse is partially obstructing them) you've got big trouble and there's a decent chance that significant internal damage in the form of excessive wear has already occurred. There are no safe ways to clean the airbox short of a teardown; the "boxed-in" situation arises when you have gunk in the ports or above their level and yet the engine is running ok - you're damned if you try to clean them and liberate some of it or get it in the cylinders, and you could be damned if you don't and it breaks free and goes in there.

The blanket involved needs replacement too, while its not oil (immediate fire risk) the soot does fairly serious damage to the insulation quality of the blanket. Turbo blankets are relatively cheap (~100 or so); change it once you find and fix the leak.

Get some pictures of the airboxes and liner ports up here.

[Banshee36]

happened to a buddys boat. try a new clamp, but check the flanges, they may be eaten up.
JW

[Angela]

Karl, where do you find turbo blankets for $100 or so? I'd like to have four new ones at prices like that!

[MikeP]

The circular clamps used on these turbo installations are a poor way to connect things together and, as noted, should be checked. I have rebuilt turbo's in the past and it's not really difficult though considerable care needs to be taken. Turbo rebuild kits used to be readily available but I haven't done one in years so I don't know if they still are. But they should be for these common AirResearch units if you are interested in doing it yourself.

Seems like a lot of soot from the engine to me also but, of course, if it's been deposited over a long period of time, it may not be an issue...

Re those turbo blankets - Count me in on those $100/set.

Two years ago I priced them from some company recommended here (can't remember what company at the moment) and got a quote of something like $1500. So I'm definitely interested in the $100 buck versions!

[Bugsy]

Karl, where do you find turbo blankets for $100 or so? I'd like to have four new ones at prices like that!

Contact Joaquim Cartaya 305-266-9897

A few years ago now but for 692's I got turbo blanket G5; turbo sweep G8 and special strip G8 all for $170.00

He's at 8221 SW 13th Terrace
Miami

I was looking for a "deal" on replacement Walker filters in FLL (didn't get one) but they knew Joaquim.

[Bugsy]

Add...that was one side, of course.

[SKYCHENEY]

You can clean the blankets. Spray them with Soot-Out and then rinse them off and let dry. That is the least of the worries here. You first have to get that leak fixed. Since it appears not to be just be an outlet leak that you could seal with Silkolene and a new clamp, the turbo will probably have to come off. As long as you have it off, take to a turbo shop and have it rebuilt. The last one of those AR turbos that I took in was about $400 for the rebuild.

[John Dickson]

Thanks for the comments guys... took the top of the intercooler off, its pretty caked up. Will pull the airbox covers and take some pics too. I am winter stored in water inside (in Michigan) so I cannot start engines till spring when the doors open. I would like to have the turbo repaired this winter if I need to - it still spins fine - I will also check the whole exhaust side for leaks too as I have quite an "exhaust spray pattern on the port fuel tank 2 x 3 ft pattern (out board of the turbo).

The boat and likely the turbo too are twenty three years young. Would you recommend rebuilding the turbo anyway at this point? Whats the process for removing the bolts from the flange? They look pretty corroded.

Will also tear down the intercooler for cleaning. Guess the airbox inspection will tell the bottom line :-(

[Genesis]

Take the turbo off and look at the exhaust flange on your collector and the turbo.

It looked to me like the leak wasn't at the flange as the V-clamp there wasn't covered in it - which means odds are the leak is at the center-housing to exhaust housing joint. That's a crappy deal as those are nearly impossible to successfully reseal in the field - I'd either swap the turbo for a rebuilt or take it to a turbo shop and have them do it. Odds are there's erosion damage to the sealing surfaces and the tolerances involved are tight. You can rebuild these yourself but IMHO its not worth it. Using Sikaflex there can be done but its not safe due to the risk of the material getting loose in the exhaust side and impacting the wheel with catastrophic results.

If the leak is at the flange between the collector and turbo you can clean that up and seal with Sikaflex. It smokes like hell the first time it gets hot - it basically "cooks" into a seal. Works really well. But like I said, I doubt the problem is there due to the lack of soot on the clamp at the joint.

If the intercooler is caked with soot it has to be cleaned (that's not difficult; brake cleaner sprayed on the air side - out of the boat please! - will remove it easily); the bigger problem is potentially in the airbox. Let's see what 'ya got - if you're lucky the deposits aren't serious and you can just leave that alone, clean the intercooler and either have the turbo rebuilt or replace it with a rebuilt unit.

If there is no gasket on the outlet from the turbo to the collector use Sikaflex when you reassemble, and ALWAYS use new "V" clamps. NEVER NEVER reuse those on the hot side - if you have one break while the boat is running you're done as the entire engine room will be filled with soot immediately and there is a significant risk of an engine-room fire; the exhaust gas can exceed 1000F.